SafePlants

Giant Milkweed (Calotropis gigantea)

Also known as Crown Flower, Giant Calotrope, and Gigantic Swallow-wort, Calotropis gigantea is a fascinating plant with a unique role in supporting Monarch butterflies.

Considerations for Pets

• Calotropis gigantea, a type of milkweed, produces a milky sap.

Considerations for Children

• Calotropis gigantea, a type of milkweed, produces a milky sap.

Taxonomy and Nomenclature

• Scientific Name: Calotropis gigantea
• Common Names: Crown Flower, Giant Calotrope, Giant Milkweed, Gigantic Swallow-wort
• Related Species: Relative of the hoya and the scarlet milkweed.

General Information and Habitat

• Calotropis procera is also known as a milkweed tree.
• Can be grown as an annual in colder climates.

Morphological Characteristics

• Described as a soft-wooded, evergreen or semi-deciduous shrub or small tree.

Ecological Role

• Host plant and nectar flower for Monarch butterflies.

Common Milkweed (Asclepias syriaca)

Asclepias syriaca, commonly known as common milkweed, butterfly flower, silkweed, or silky swallow-wort, is a native perennial that plays a vital role in supporting monarch butterfly populations and numerous other insect species.

Considerations for Pets

• Named for its milky sap.

Considerations for Children

• Named for its milky sap.

Taxonomy and Nomenclature

• Scientific Name: Asclepias syriaca
• Common Names: Common Milkweed, Butterfly Flower, Silkweed, Silky Swallow-wort

General Information and Habitat

• A native perennial plant found in prairies.

Morphological Characteristics

• Upright specimen that may reach 2 to 6 feet tall. Some sources state 3-6 feet.
• Stout, erect perennial with a straight, sturdy, hollow stem.
• Unbranching stem, typically three to six feet tall.
• Opposite, dark-green leaves, large (6-8 inches long). Some sources state 4 to 8 inches long and 2 to 4 inches wide.
• Large, broad leaves, usually up to ten inches long. Some sources state leaves ranging from 10 to 18 cm long, oval shaped.
• Produces pairs of large, oblong, thick leaves.
• Flower consists of a large cluster of individual flowers.
• Large flower can vary in the color range from nearly white to deep pink-purple. Umbels bear large balls of pink to purplish flowers that have an attractive odor.
• Large (12 cm long) seed pods, called follicles, form after flowering. Spindle-shaped seedpods after pollination.
• Seeds, each with long, white flossy hairs, occur in large follicles.
• Large, elongated tear-drop shaped seed pods that the plant produces during late summer.
• Large fruits are light green and contain numerous densely packed, bearded seeds.

Ecological Role

• Important plant because so many species of insects depend on it.
• Main food plant for monarch butterfly larvae.
• The butterfly's dramatic decline has been driven in large part by the increasing scarcity of its only caterpillar host plant: milkweed.
• Monarch butterflies lay their eggs exclusively on Milkweed plants.
• One of the biggest factors in monarch decline is the increasing scarcity of its only caterpillar host plant: milkweed. Without milkweed, monarchs cannot survive.
• Monarch butterfly needs milkweed as a larval host plant.

Quirky Facts

• In the language of flowers, milkweed means hope in misery.

Historical Uses

• Externally, Milkweed has been used in traditional medicine.
• Flower buds first appear in early summer and can be harvested for food.
• Boil a large handful of silk wads with a pot of rice or cous cous.

Other Milkweed Varieties

• Butterfly Milkweed (Asclepias tuberosa L.): One of the most striking native wildflowers. Flower color is generally orange to red. Easiest to establish as a young plant but due to its large taproot, mature plants are not easy to move.
• Showy Milkweed (Asclepias speciosa): Beautiful plant in bloom, with large fragrant clusters of pink-tinged white flowers. Its form is similar to Common Milkweed, but the flower clusters are held more upright.